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I don't have the calculator :( Add some details

Thanks!

I don't have the calculator :( Add some details Thanks!-example-1
User Helt
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1 Answer

5 votes

\sin2x-\sin x=2\sin x\cos x-\sin x=\sin x(2\cos x-1)=0


\implies\sin x=0\text{ or }2\cos x-1=0

From the first equation, we get two possible solutions at
x=0 and
x=\pi\approx3.14.

From the second equation, we get


2\cos x-1=0\implies\cos x=\frac12

which has exact solutions at
x=\frac\pi3 and
x=\frac{5\pi}3. Since
\pi\approx3.14, we can approximate these solutions by
x=\frac\pi3\approx1.05 and
x=\frac{5\pi}3\approx5.24.
User Muhammad Taqi
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8.5k points